Simplify the following expression: $n = \dfrac{y}{10} + \dfrac{y}{7}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $10$ and $7$ $\lcm(10, 7) = 70$ $ n = \dfrac{7}{7} \cdot \dfrac{y}{10} + \dfrac{10}{10} \cdot \dfrac{y}{7} $ $n = \dfrac{7y}{70} + \dfrac{10y}{70}$ $n = \dfrac{7y +10y}{70}$ $n = \dfrac{17y}{70}$